Configuring MongoDB Liquibase in Spring Boot

The version of Spring Boot we will be using is 2.7.4 . The dependencies we need are as follows.

  <dependency>
   <groupId>org.liquibase.ext</groupId>
   <artifactId>liquibase-mongodb</artifactId>
   <version>4.15.0</version>
  </dependency>
  <dependency>
   <groupId>org.liquibase</groupId>
   <artifactId>liquibase-core</artifactId>
   <version>4.15.0</version>
  </dependency>
  <dependency>
   <groupId>org.springframework.data</groupId>
   <artifactId>spring-data-mongodb</artifactId>
   <version>3.4.3</version>
  </dependency>

We need to define the url to connect to the Mongo database, the username and password of the user that has writing and reading permissions and also the changeLogFilePath which is the path to the changelog file. In the following example, the changelog file is stored in resources > db > changelog .

String url = "";
String username = "";
String password = "";
String changeLogFilePath = "classpath:db/changelog/changelog.json";

Next, we need to create the MongoLiquibaseDatabase class which opens the connection to the Mongo database.

// we pass the url to the database, the username and the password
MongoLiquibaseDatabase database = (MongoLiquibaseDatabase) DatabaseFactory.getInstance().openDatabase(
    url, username, password, null,
    new ClassLoaderResourceAccessor());

We create the Liquibase class which offers the methods and functions to operate using liquibase onto Mongo. We pass to it the MongoLiquibaseDatabase object we created above.

// changeLogFilePath is the path to the changelog file
Liquibase liquibase = new Liquibase(changeLogFilePath, new ClassLoaderResourceAccessor(), database);

Now, we can execute the changelog file.

List<ChangeSet> changeSetsList = liquibase.listUnrunChangeSets(null, null);
 if (!changeSetsList.isEmpty()) {
  liquibase.update("");
 }

In the above method, we check if there are any unrun changesets. If there are, we execute the update method that executes the new updates on the changelog file.

To make all the pieces together, look at the following code that uses try-with-resources to ensure the close of connection to the Mongo database in case of failure.

try (MongoLiquibaseDatabase database = (MongoLiquibaseDatabase) DatabaseFactory.getInstance().openDatabase(
    url, username, password, null,
    new ClassLoaderResourceAccessor());
    Liquibase liquibase = new Liquibase(changeLogFilePath, new ClassLoaderResourceAccessor(), database);) {

   List<ChangeSet> changeSetsList = liquibase.listUnrunChangeSets(null, null);
   if (!changeSetsList.isEmpty()) {
    liquibase.update("");
   }

  } catch (LiquibaseException e) {
     log.error("error running liquibase {}", e.getMessage());
  }

The changelog file might be as follows.

{
  "databaseChangeLog": [
    {
      "include": {
        "file": "db/changelog/01-create-test.json"
      }
    },
    {
      "include": {
        "file": "db/changelog/02-populate-test.json"
      }
    }
  ]
}